New Model for VDT Associated Visual Comfort in Office Spaces
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Niloofar Moghbel New Model for VDT Associated Visual Comfort in Office Spaces Dissertation Department of Architecture Karlsruhe Institute of Technology (KIT) New Model for VDT Associated Visual Comfort in Office Spaces Zur Erlangung des akademischen Grades eines Doktor-Ingenieurs von der Fakultät für Architektur des Karlsruher Instituts für Technologie (KIT) genehmigte Dissertation von Niloofar Moghbel Tag der mündlichen Prüfung: 19. April 2012 Referent: Prof. Dipl.-Ing. Andreas Wagner, Karlsruhe Korreferent: Prof. Dr. Sc. nat. Christoph Schierz, TU Ilmenau Weiteres Mitglied: Prof. Dr. Ing. Rosemarie Wagner Vorsitzender: Prof. Dipl.-Ing. Matthias Pfeifer 2 Acknowledgements This thesis has been carried out during my tenure at the Fraunhofer Institute for Solar Energy Systems (ISE) in Freiburg, Germany. I am indebted to the Fraunhofer ISE for providing me with an excellent scientific environment, financial support and research facilities. I appreciate Prof. Weber, Dr. Henning, S. Herkel. T. Kuhn and J. Wienold for their support to realize and conduct this work. My Ph.D. thesis has been conducted within the framework of a DFG funded project (QUANTA). I acknowledge the QUANTA partners, Fraunhofer Institute for Solar Energy Systems (Freiburg) and department of Architecture at the Karlsruhe Institute of Technology (KIT). I want to thank Prof. Andreas Wagner for accepting me as a Ph.D. student at the department of Architecture of the Karlsruhe Institute of Technology (KIT), Germany and for supervising my Ph.D. thesis. Many thanks to Prof. Christoph Schierz (TU Ilmenau, D) for accepting to be the co-advisor of my thesis, for all his kind support and advice whilst conducting this research including performing the experimental procedure in person described in chapter 5 which provided valuable insight. Many thanks also to my supervisor at Fraunhofer ISE, Jan Wienold, for his help and constant advice, for all the fruitful discussions we had during this research work and for proof reading my thesis and his valuable comments which enhanced the quality. I must thank Sebastian Herkel for all his generous support during my tenure in the solar building department at the Fraunhofer ISE and for inspiring and motivating me to realize and finalize my research project. My special thanks to Gregory Ward (Anyhere Software, CA). Discussion with Greg during the 5th RADIANCE workshop (2006) in Leicester helped me to direct my project to its current framework; his generous advice helped me get started with RADIANCE simulations and defining the project outlines. Many thanks to Prof. Michael Bach (Uni. Eye clinic Freiburg, D) for his helpful advice in designing the experimental study described in chapter 5 and for kindly accepting to conduct the whole experiment in person. I would specially like to thank Prof. S. Kokoschka for our precious discussion at the Karlsruhe Institute of Technology and his valuable advice which helped me 3 finalize designing the Landolt ring test described in chapter 4. My cooperation with Christian Reetz (Riap, D) in performing the Lab- measurement of a visual display and the consequent material-modeling, described in chapter 7, was a thoroughly pleasant experience. Thanks a lot Christian for your kind support whenever it was needed and for the proof reading and for your valuable comments on chapter 7. I would like to thank Dr. Rainer Leonhart (Uni. Freiburg) for advising me regarding my statistical questions by developing the MRC model described in chapter 6. I also thank Augustinus Topor for the nice cooperation in developing a computer tool for veiling glare by providing me with the C-programmed scripts to automate the procedure (chapter 8). Most of all I appreciate my parents for providing me with the opportunities to follow my aims and wishes and for their unconditional love and support during the highs and lows throughout this work. 4 Content Kurzfassung ............................................................................................................... 7 Executive summary ................................................................................................. 13 1 Introduction ................................................................................................... 19 1.1 Motivation .............................................................................................. 19 1.2 Objectives ............................................................................................... 20 1.3 General outline ....................................................................................... 21 1.4 Background of the Thesis ........................................................................ 22 2 Review of existing methods - Aspects of visual discomfort or glare ......... 24 2.1 Discomfort glare...................................................................................... 24 2.2 Disability glare ......................................................................................... 25 2.3 Veiling glare ............................................................................................ 26 2.3.1 Veiling glare on visual displays ............................................................ 26 2.3.2 Summary and discussion ..................................................................... 36 3 Experimental study to show the importance of veiling glare evaluation . 38 3.1 Method ................................................................................................... 38 3.1.1 Project methodology .......................................................................... 38 3.1.2 Experimental procedure ...................................................................... 43 3.2 Results .................................................................................................... 50 3.3 Discussion ............................................................................................... 53 4 Experimental study to evaluate existing contrast threshold ...................... 55 4.1 Method ................................................................................................... 55 4.1.1 Project methodology .......................................................................... 55 4.1.2 Experimental Procedure ...................................................................... 60 4.2 Results .................................................................................................... 67 4.2.1 Data evaluation .................................................................................. 68 4.3 Discussion and Outlook ........................................................................... 74 5 Experimental study to evaluate contrast and readability on VDTs ............ 77 5.1 Method ................................................................................................... 77 5.1.1 Project methodology .......................................................................... 77 5.1.2 Experimental Procedure ...................................................................... 89 5.2 Results .................................................................................................... 95 5.2.1 Calculation of final text-contrast ......................................................... 95 5.2.2 Calculation of average environmental luminance ................................ 96 5.2.3 Evaluation of minimum required contrast ............................................ 97 5.2.4 Evaluation of the data ........................................................................ 99 5.3 Summary and discussion ....................................................................... 101 6 MRC Model development ............................................................................ 103 6.1 Method ................................................................................................. 103 6.1.1 Project methodology ........................................................................ 103 6.1.2 Experimental Procedure .................................................................... 103 6.2 Results .................................................................................................. 110 6.2.1 Pearson correlation ........................................................................... 110 6.2.2 Relative root mean square error (rRMSE) analysis ............................... 112 5 6.2.3 Boot-strapping ................................................................................. 113 6.2.4 Intra-Class Correlation ...................................................................... 114 6.2.5 Testing the developed model against other datasets ......................... 114 6.2.6 Robustness of the model to extreme values ...................................... 116 6.3 Conclusion and outlook ........................................................................ 118 7 Computer based model for evaluating veiling glare ................................ 120 7.1 Measurements and modeling of a LCD monitor ..................................... 120 7.1.1 Introduction ..................................................................................... 120 7.1.2 Measurements.................................................................................. 120 7.1.3 Modeling procedure ......................................................................... 123 7.2 Simulation-based veiling glare evaluation ............................................... 129 7.2.1 Determining a pattern as screen image ............................................